X-ray irradiation apparatus

ABSTRACT

An X-ray beam emitter including a vacuum chamber having a target window. An electron generator is positioned within the vacuum chamber for generating electrons that are directed at the target window for forming X-rays. The X-rays pass through the target window in an X-ray beam.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/277,322 filed on Mar. 20, 2001. The entire teachings of the aboveapplication are incorporated herein by reference.

BACKGROUND

Many medical instruments are reusable and require sterilization betweenuses. Some of these instruments, for example, endoscopes andgastroscopes, are difficult to fully sterilize. Typically, suchinstruments are sterilized by hydrogen peroxide which is flushed throughthe interior as well as over the exterior of the instruments. This isnot only a time consuming process, taking about one hour, but often theinstruments have contaminated areas which the sterilizing process cannotsufficiently penetrate to fully sterilize such as biofilms of bacteria.In addition, the hydrogen peroxide is not able to kill all viruses.Another common sterilization agent is ethylene oxide which producessimilar results. Other methods of sterilization include irradiation withgamma radiation, but this method can take up to 24 hours with currentequipment.

SUMMARY

The present invention includes an apparatus that can be employed forsterilizing articles such as medical instruments more quickly andthoroughly than current methods. The present invention includes an X-raybeam emitter having vacuum chamber with a target window. An electrongenerator is positioned within the vacuum chamber for generatingelectrons that are directed at the target window for forming X-rays. TheX-rays pass through the target window in an X-ray beam.

In particular embodiments, the target window has a thickness whichsubstantially prevents the passage of electrons therethrough. Theelectrons and X-ray beam travel in substantially the same direction. TheX-ray beam is directed into an irradiation region for irradiatingarticles positioned therein. In some embodiments, the emitter is asterilization device where articles irradiated by the X-ray beam aresterilized.

The X-ray beam emitter can be part of an X-ray beam system in an X-rayirradiation apparatus which includes at least one X-ray beam emitter fordirecting at least one X-ray beam into an irradiation region. Inparticular embodiments, the X-ray beam system includes more than oneX-ray beam emitter for directing X-ray beams into the irradiation regionfrom different directions. In one embodiment, at least three X-ray beamemitters are positioned around the irradiation region thereby forming acentral irradiation chamber. In another embodiment, six X-ray beamemitters are positioned in a ring around the irradiation region and abutagainst each other. The X-ray beam system may include more than one ringof X-ray beam emitters which are joined together. In some embodiments,the apparatus is a sterilization apparatus where articles are positionedwithin the irradiation chamber for sterilization.

The present invention also includes a method of forming X-rays. Themethod includes providing a vacuum chamber having a target window. Anelectron generator is positioned within the vacuum chamber forgenerating electrons. The electrons are directed at the target window toform X-rays which pass through the target window in an X-ray beam. Thetarget window has a thickness which substantially prevents the passageof electrons therethrough. The electrons and the X-ray beam travel insubstantially the same direction.

When employed for sterilization purposes, the X-ray beams generated byembodiments of the present invention are able to deeply penetrate intothe articles being irradiated. Both surface and imbedded contaminantsare able to be irradiated for relatively quick and thoroughsterilization in comparison to traditional methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a simplified end view of an embodiment of the presentinvention X-ray beam irradiation apparatus.

FIG. 2 is a simplified perspective view of the X-ray beam irradiationapparatus of FIG. 1.

FIG. 3 is a side view of another embodiment of the present inventionX-ray beam irradiation apparatus.

FIG. 4 is an end sectional view of an embodiment of an X-ray beamemitter in accordance with the present invention.

FIG. 5 is a side sectional view of the X-ray beam emitter of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, X-ray beam irradiation apparatus 10 issuitable for sterilizing objects or articles, for example, medicalinstruments, tools or components. In the embodiment depicted in FIGS. 1and 2, X-ray beam irradiation apparatus 10 includes an x-ray beam systemhaving an X-ray irradiation unit 11 for irradiating articles 19. TheX-ray irradiation unit 11 of the embodiment depicted in FIGS. 1 and 2includes a series of X-ray beam emitters 12 each having a target window16 through which an X-ray beam 22 is generated. The X-ray beam emitters12 have angled side walls 14 which allow the X-ray beam emitters 12 tobe abutted against each other and joined together in a ring 10 asurrounding an irradiation region or chamber 20 so that the X-ray beamemitters 12 can direct the X-ray beams 22 radially inwardly intoirradiation chamber 20 from different directions. FIGS. 1 and 2 depictsix X-ray beam emitters 12 abutted against each other to form ahexagonal shaped irradiation chamber 20. The target windows 16 areclosely positioned to each other so that the X-ray beams 22 directedinto irradiation chamber 20 combine to provide substantially continuousradially inward X-ray beam coverage.

In use, articles 19 (FIG. 1) such as medical instruments requiringsterilization are typically positioned within irradiation chamber 20.Doors, such as those shown in FIG. 3, designated by reference numeral26, may be employed on opposite ends of irradiation chamber 20 toprovide shielding of the X-rays. Alternatively, elongated entrance andexit tunnels can be employed to provide shielding. Power to the X-raybeam emitters 12 is then provided so that X-ray beams 22 are directedinwardly into irradiation chamber 20. The X-ray beams 22 are able todisable, damage or kill bacteria, viruses, and organisms on the surfaceof the article 19. In addition, the X-ray beams 22 can penetrate intothe article 19 to sterilize regions deep within the article 19 as wellas penetrate and sterilize thick layers or regions of contamination.Instruments such as an endoscope may require a sterilization time ofabout a half hour at a low power of 5 kW per emitter 12 to achievethorough sterilization. This is about half the time in comparison to theone hour typically required when sterilizing with hydrogen peroxide.Even over such an amount of time, instruments sterilized by hydrogenperoxide are not as thoroughly sterilized as in the present invention.

Although six X-ray beam emitters 12 are shown in FIGS. 1 and 2 to formX-ray irradiation unit 11, it is understood that any number of X-raybeam emitters 12 can be employed. When three emitters 12 are employed,irradiation chamber 20 can be triangular in shape, with four emitters12, square, and with five and above, polygonal. When multiple emitters12 are employed, irradiation chamber 20 can also have configurationsthat are wide and flat, or convoluted, depending upon the situation. Insome cases, X-ray irradiation unit 11 may only need one or two X-raybeam emitters 12. In such cases, reflectors for reflecting X-rays can beused in combination with the X-ray beam emitters 12. Additionally,although x-ray emitters 12 have been shown to be joined together in aring 10 a, alternatively, one or more X-ray emitters 12 may bepositioned for providing X-ray beams that are not in a substantiallycontinuous circle, for example, from one or two directions. When twoX-ray beam emitters 12 are employed, the emitters 12 can be arranged inopposed fashion.

Referring to FIG. 3, X-ray beam irradiation apparatus 24 is employedwhen sterilizing articles 19 that are too long to fit within apparatus10. X-ray beam irradiation apparatus 24 includes an X-ray beam systemhaving more than one X-ray irradiation unit 11 joined together. In oneembodiment, each X-ray irradiation unit 11 includes a ring 10 a of X-raybeam emitters 12 similar to that depicted in FIGS. 1 and 2. The rings 10a are abutted against each other and joined together so that theirradiation chambers 20 of each ring 10 a join together collectively toform one long irradiation region or chamber 28. Three X-ray irradiationunits 11 are shown abutted together, however, less than three or morethan three units 11 can be joined together. Typically, X-ray beamirradiation apparatus 24 includes doors 26 to provide shielding of theX-rays. Although instruments are typically positioned in a stationarymanner within irradiation chamber 28, alternatively, a conveyor systemcan be employed to slowly move articles 19 through irradiation chamber28. The conveyor system may include conveyor belts and/or rollers. Whena conveyor system is employed, entrance and exit tunnels may bedesirable to provide shielding.

It is understood that X-ray irradiation apparatus 24 can have X-rayirradiation units 11 of configurations that are different than ring 10 asuch as discussed above. In addition, some embodiments of theirradiation units 11 can include mechanisms for moving one or moreemitters 12 over or around an article 19 for providing X-ray irradiationwith a minimum number of emitters 12. In one embodiment, a ring 10 a istranslated longitudinally along article 19. In another embodiment, anemitter 12 is rotated around article 19 and can also be translatedlongitudinally over article 19. In configurations where an emitter 12 isrotated around article 19, employing more than one emitter 12 can reducethe amount of rotation required. For example, if two emitters 12 areemployed positioned in opposed fashion, the emitters 12 can be rotatedonly 180° around article 19.

In addition to sterilizing medical instruments, tools or components,X-ray beam irradiation apparatuses 10 and 24 can be employed tosterilize implantable devices or components such as artificial joints,pins, plates, pumps, pacemakers, etc. Furthermore, a wide variety ofobjects or articles 19 can be sterilized, including items for use in asterile room or environment. In some instances, it may be desirable tosterilize substances such as powders, liquids or food items. Referringto FIG. 3, X-ray beam irradiation apparatus 24 can be employed as asterilizing entrance for articles 19 entering a sterile environmentwhere one end of apparatus 24 is connected to the sterile environment,typically, extending through a wall thereof. One door 26 allows articles19 to be inserted into apparatus 24 from the exterior for sterilization.The other door 26 allows removal of the sterilized article 19 fromapparatus 24 into the sterile environment.

Referring to FIGS. 4 and 5, X-ray beam emitter 12 in one embodimentincludes a hermetically sealed vacuum chamber 30 having a rectangulartarget window 16 positioned at one end thereof. An electron generator 32is positioned within the interior 30 a of vacuum chamber 30 forgenerating electrons e⁻ which are accelerated towards the target window16 for forming X-rays. The target window 16 typically consists of a thinmetallic foil that has a thickness sufficient to substantially preventthe passage of electrons e⁻ through while allowing passage of X-rays.The target window 16 is supported by a support plate 38 having a seriesof holes 38 a therethrough which allow the electrons e⁻ to reach targetwindow 16. In some embodiments, outwardly angled holes 38 b may beincluded at the far ends of support plate 38 (FIG. 5) to direct moreelectrons e⁻ to the ends of target window 16. The target window 16 issealed to support plate 38 by bonding under heat and pressure, butalternatively could be brazed or welded. In one embodiment, the targetwindow 16 can be 12 inches long so that irradiation chamber 20 is about12 inches long. When X-ray beam emitters 12 are to be abutted againsteach other in a ring such as ring 10 a (FIG. 1), the emitters 12 canhave angled sides 14 which extend towards and near the longer sides ofthe target window 16 (FIG. 4). Sides 14 are angled at about 60° when sixemitters 12 are abutted together, however, the angle of sides 14 candiffer depending upon the number of emitters 12 joined together. In someirradiation chamber 20 configurations, the angled sides 14 can beomitted, for example, in some rectangular configurations. A tube may beextended from vacuum chamber 30 and connected to a vacuum pump forevacuating vacuum chamber 30 which is then sealed off to hermeticallyseal vacuum chamber 30.

The electron generator 32 has a filament housing 34 which in oneembodiment is disc shaped and has a series of openings in the bottom 34a. Tungsten filaments 36 are positioned within housing 34 for generatingthe electrons e⁻. Filament housing 34 is electrically connected to ahigh voltage supply by tubular conductor 40 a and cable 18. Commonranges are 100-300 kV with 125 kV being typical. In some applications,voltages 100 kV and above 300 kV may be desirable. Target window 16 iselectrically grounded to impose a high voltage potential betweenfilament housing 34 and target window 16. Filaments 36 are providedpower by a filament power supply electrically connected to cable 18 andare electrically connected at one end to a conductor 42 extending withinthe interior of filament housing 34, and are electrically connected atthe other end to a conductor 40 b extending from cable 18. The upperportions of conductor 40 a is embedded within insulating materials 44.

In use, the filaments 36 are provided with power to heat filaments 36 toabout 3400° F. to 4200° F. which causes free electrons e⁻ to form onfilaments 36. The high voltage potential imposed between the filamenthousing 34 and target window 16 causes the free electrons e⁻ onfilaments 36 to accelerate from the filaments 36 in a beam throughopenings in the bottom 34 a of filament housing 34 to target window 16.The target window 16 is typically a thin foil of gold, titanium ortungsten about 3 microns thick which substantially blocks or preventsthe passage of electrons e⁻ therethrough, but, alternatively, may beformed of titanium with a layer of gold thereon, or be formed of goldwith copper or silver. Typically, metals with a high Z number and goodthermal conductivity are preferred, but it is understood that thematerial of target window 16 can vary depending upon the application athand. For example, materials and combinations other than those describedabove can be used. The electrons e⁻ striking the target window 16typically do not pass through but instead form X-rays which exit oremerge from the target window 16 in an X-ray beam 22 and continue totravel substantially in the same forward direction as the electrons e⁻were traveling. In other words, the beam of electrons e⁻ is transformedor changed by target window 16 into the X-ray beam 22 resulting in acontinuous two-part or stage beam where the first stage is formed by thebeam of electrons e⁻ and the second stage is formed by the X-ray beam22. The X-ray beam 22 exits target window 16 with substantially the sameoutline as target window 16. The production of X-rays in this mannerprovides a relatively efficient broad X-ray beam 22 because both theelectrons e⁻ and the X-ray beam 22 are traveling in the same forwarddirection. The beam of electrons e⁻ and the X-ray beam 22 are shown tobe perpendicular or substantially perpendicular to target window 16. Insome situations, electrons e⁻ might strike target window 16 at an angle.

In some embodiments, target window 16 may be configured to allow someelectrons e⁻ to pass through to provide a mix of electrons e⁻ andX-rays. In further embodiments, the target window 16 can be replaced byan electron beam exit window which allows the electrons e⁻ to exit theemitters 12 in an electron beam. In such a case, the electrons e⁻ strikethe surface of the article to be sterilized thereby sterilizing thesurface and, at the same time, creating X-rays which sterilize theinterior. Such an embodiment can be used to sterilize or decontaminateany type of suitable equipment. The target window 16 can be configuredto suit particular arrangements, and can be of shapes other thanrectangular.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. For example, features of the variousembodiments discussed above may be combined with each other or omitted.It is understood that the configuration, shape, dimensions, size andpower of X-ray emitter 12 can be varied depending upon the applicationat hand as well as the shape of the target window 16. Multiple emitters12 may be positioned side by side for generating an X-ray beam 22 fromone direction, or positioned in opposing directions for generating X-raybeams 22 from two directions. In some configurations, the X-ray beams 22from emitters 12 are not joined in a continuous manner. In addition,X-ray emitters 12 and apparatuses 10 and 24 may be employed to sterilizeany desired article, or may be used for other typical purposes, such astaking an X-ray of a patient or curing coatings.

What is claimed is:
 1. An X-ray beam emitter comprising: a vacuumchamber having a target window; and an electron generator positionedwithin the vacuum chamber for generating electrons that are directed atthe target window for forming X-rays which pass through the targetwindow in an X-ray beam, the target window being supported by a supportplate having a series of holes therethrough which allow passage of theelectrons therethrough to reach the target window.
 2. The emitter ofclaim 1 in which the target window has a thickness which substantiallyprevents the passage of electrons therethrough.
 3. The emitter of claim2 in which the electrons and X-ray beam travel in substantially the samedirection.
 4. The emitter of claim 3 further comprising an irradiationregion into which the X-ray beam is directed for irradiating articles.5. The emitter of claim 4 in which the emitter is a sterilization devicewhere articles irradiated by the X-ray beam are sterilized.
 6. An X-rayirradiation apparatus comprising: an X-ray beam system for directing atleast one X-ray beam into an irradiation region, the X-ray beam systemcomprising at least one X-ray beam emitter, said X-ray beam emittercomprising: a vacuum chamber having a target window; and an electrongenerator positioned within the vacuum chamber for generating electronsthat are directed at the target window for forming X-rays which passthrough the target window as said X-ray beam, the target window beingsupported by a support plate having a series of holes therethrough whichallow passage of the electrons therethrough to reach the target window.7. The apparatus of claim 6 in which the target window of the X-ray beamemitter has a thickness which substantially prevents the passage ofelectrons therethrough.
 8. The apparatus of claim 7 in which theelectrons and X-ray beam travel in substantially the same direction. 9.The apparatus of claim 8 in which the X-ray beam system comprises morethan one X-ray beam emitter for directing X-ray beams into theirradiation region from different directions.
 10. The apparatus of claim8 in which the X-ray beam system comprises at least three X-ray beamemitters positioned in a ring around the irradiation region, therebyforming a central irradiation chamber.
 11. The apparatus of claim 9 inwhich the X-ray beam system comprises six X-ray beam emitters positionedin a ring around the irradiation region and abutting each other.
 12. Theapparatus of claim 10 in which the X-ray beam system comprises more thanone ring of X-ray beam emitters joined together.
 13. The apparatus ofclaim 8 in which the apparatus is a sterilization apparatus wherearticles are positioned within the irradiation chamber forsterilization.
 14. The apparatus of claim 8 in which the X-ray beamsystem comprises at least one irradiation unit having at least one X-raybeam emitter.
 15. The apparatus of claim 14 in which the X-ray beamsystem comprises more than one irradiation unit joined together.
 16. AnX-ray sterilization apparatus comprising: an X-ray beam system fordirecting at least one X-ray beam into an irradiation region, the X-raybeam system comprising at least one X-ray beam emitter, said X-ray beamemitter comprising: a vacuum chamber having a target window; and anelectron generator positioned within the vacuum chamber for generatingelectrons that are directed at the target window for forming X-rayswhich pass through the target window as said X-ray beam, said X-ray beamfor sterilizing articles positioned within the irradiation zone, thetarget window being supported by a support plate having a series ofholes therethrough which allow passage of the electrons therethrough toreach the target window.
 17. A method of forming an X-ray beam emittercomprising: providing a vacuum chamber having a target window; andpositioning an electron generator within the vacuum chamber forgenerating electrons that are directed at the target window for formingX-rays which pass through the target window in an X-ray beam, the targetwindow being supported by a support plate having a series of holestherethrough which allow passage of the electrons therethrough to reachthe target window.
 18. The method of claim 17 further comprisingproviding the target window with a thickness which substantiallyprevents the passage of electrons therethrough.
 19. The method of claim18 further comprising configuring the X-ray beam emitter so that theelectrons and X-ray beam travel in substantially the same direction. 20.The method of claim 19 further comprising forming an irradiation regioninto which the X-ray beam is directed for irradiating articles.
 21. Amethod of forming an X-ray irradiation apparatus comprising: forming anX-ray beam system for directing at least one X-ray beam into anirradiation region, the X-ray beam system comprising at least one X-raybeam emitter; and providing the X-ray beam emitter with a vacuum chamberhaving a target window, and an electron generator positioned within thevacuum chamber for generating electrons that are directed at the targetwindow for forming X-rays which pass through the target window as saidX-ray beam, the target window being supported by a support plate havinga series of holes therethrough which allow passage of the electronstherethrough to reach the target window.
 22. The method of claim 21further comprising providing the target window with a thickness whichsubstantially prevents the passage of electrons therethrough.
 23. Themethod of claim 22 further comprising configuring the X-ray beam emitterso that the electrons and X-ray beam travel in substantially the samedirection.
 24. The method of claim 23 further comprising providing theX-ray beam system with more than one X-ray beam emitter for directingX-ray beams into the irradiation region from different directions. 25.The method of claim 23 further comprising providing the X-ray beamsystem with at least three X-ray beam emitters positioned in a ringaround the irradiation region, thereby forming a central irradiationchamber.
 26. The method of claim 25 further comprising positioning sixX-ray beam emitters in a ring around the irradiation region and abuttingeach other.
 27. The method of claim 25 further comprising forming theX-ray beam system from more than one ring of X-ray beam emitters joinedtogether.
 28. The method of claim 23 further comprising providing theX-ray beam system with at least one irradiation unit having at least oneX-ray beam emitter.
 29. The method of claim 28 further comprisingjoining more than one irradiation unit together to form the X-ray beamsystem.
 30. The method of claim 22 further comprising forming theapparatus into a sterilization apparatus for sterilizing articlespositioned within the irradiation region.
 31. A method of forming anX-ray sterilization apparatus comprising: forming an X-ray beam systemfor directing at least one X-ray beam into an irradiation region, theX-ray beam system comprising at least one X-ray beam emitter; andproviding the X-ray beam emitter with a vacuum chamber having a targetwindow, and an electron generator positioned within the vacuum chamberfor generating electrons that are directed at the target window forforming X-rays which pass through the target window as said X-ray beam,said X-ray beam for sterilizing articles positioned within theirradiation zone, the target window being supported by a support platehaving a series of holes therethrough which allow passage of theelectrons therethrough to reach the target window.
 32. A method offorming X-rays comprising: providing a vacuum chamber having a targetwindow; positioning an electron generator within the vacuum chamber forgenerating electrons; and directing the electrons at the target windowto form X-rays which pass through the target window in an X-ray beam,the target window being supported by a support plate having a series ofholes therethrough which allow passage of the electrons therethrough toreach the target window.
 33. The method of claim 32 further comprisingproviding the target window with a thickness which substantiallyprevents the passage of electrons therethrough.
 34. The method of claim33 further comprising configuring the X-ray beam emitter so that theelectrons and X-ray beam travel in substantially the same direction.